A radiating feed consists of a radiating element, for example a horn, connected to a radiofrequency (RF) system. The RF system comprises RF components making it possible to switch from a mode of guided propagation of the electromagnetic waves to a radiated mode and produces, for each beam, the functions of transmission and of reception in a particular frequency band, for example the Ka band. The transmission and reception functions can be performed in single-polarization mode to cover the needs of the users or in bi-polarization mode to ensure links to terrestrial gateway stations.
In the multibeam antenna architectures, a number of independent elementary radiating feeds are assembled in an array placed in the focal plane of a reflector. Assembling the different radiating feeds is complex because it often requires the radiating feeds to be maintained with a specific orientation making it possible to limit the phase aberrations linked to the defocusing of the horn in relation to the centre of the reflector and to maximize the performance levels of the antenna for each beam. Each radiating feed is assembled on a mechanical support by an interface specific to each horn. This individual assembly of each feed entails individually managing the interface of each RF system and the setting of the orientation of each horn, which does not make it possible to pool the production of the RF systems because their RF axes are not mutually parallel. The individual management of each feed therefore has a significant cost.
To facilitate the individual orientation of each radiating feed, as represented in FIG. 1, it is known practice to individually fix the radiating feeds onto a structural plate 13 in which distribution waveguides 14 are machined that are intended to route RF signals between the radiating feed and input/output ports of an RF signal processing device. The distribution waveguides are connected to outputs of the RF systems 10 by flexible waveguides 15 making it possible to individually orient each radiating feed. The structural plate 13 then ensures the routing of the distribution waveguides 14 as well as the support and orientation of the RF systems relative to the reflector of the multibeam antenna. However, this solution requires the RF systems to be assembled independently of one another, an individual orientation of each RF system and of the associated horn, and entails the use of numerous flexible orientation waveguides inducing additional ohmic losses and additional thermal power to be dissipated. Furthermore, this solution is possible only when the feeds of the focal array are sufficiently spaced apart from one another to allow the routing of the distribution waveguides between the RF systems supported by the structural plate.
To our knowledge, there is currently no structural antenna module comprising a set of radiating feeds whose RF systems are completely incorporated in a common support, and that allow individual orientation of the feed horns.